/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.solr.response.transform;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.response.ResultContext;
import org.apache.solr.search.DocIterationInfo;

/** Transform a document before it gets sent out */
public class DocTransformers extends DocTransformer {
  final List<DocTransformer> children = new ArrayList<>();

  @Override
  public String getName() {
    StringBuilder str = new StringBuilder();
    str.append("Transformers[");
    Iterator<DocTransformer> iter = children.iterator();
    while (iter.hasNext()) {
      str.append(iter.next().getName());
      if (iter.hasNext()) {
        str.append(",");
      }
    }
    str.append("]");
    return str.toString();
  }

  @Override
  public Collection<String> getRawFields() {
    return children.stream()
        .map(DocTransformer::getRawFields)
        .flatMap(Collection::stream)
        .collect(Collectors.toList());
  }

  public void addTransformer(DocTransformer a) {
    children.add(a);
  }

  public int size() {
    return children.size();
  }

  public DocTransformer getTransformer(int idx) {
    return children.get(idx);
  }

  @Override
  public void setContext(ResultContext context) {
    for (DocTransformer a : children) {
      a.setContext(context);
    }
  }

  @Override
  public void transform(SolrDocument doc, int docid, DocIterationInfo docInfo) throws IOException {
    for (DocTransformer a : children) {
      a.transform(doc, docid, docInfo);
    }
  }

  /** Returns true if and only if at least 1 child transformer returns true */
  @Override
  public boolean needsSolrIndexSearcher() {
    return children.stream().anyMatch(DocTransformer::needsSolrIndexSearcher);
  }
}
